Vascular disease frequently arises from the accumulation of atheromatous material on the inner walls of vascular lumens, particularly arterial lumens of the peripheral and other vasculature, especially peripheral arteries, resulting in a condition known as atherosclerosis. Atherosclerosis occurs naturally as a result of aging, but may also be aggravated by factors such as diet, hypertension, heredity, vascular injury, and the like. Atheromatous deposits can have widely varying properties, with some deposits being relatively soft and others being fibrous and/or calcified. In the latter case, the deposits are frequently referred to as plaque.
Vascular disease can be treated in a variety of ways, including drugs, bypass surgery, and a variety of catheter-based approaches, including those which rely on intravascular debulking or removal of the atheromatous or other material occluding a blood vessel. A variety of methods for cutting or dislodging material and removing such material from the blood vessel have been proposed, generally being referred to as atherectomy procedures. Atherectomy catheters intended to cut or excise material from the blood vessel lumen may employ a rotatable cutting blade (or other tissue-removing element) which can be advanced into or past the occlusive material in order to cut and separate such material from the blood vessel lumen.
Although atherectomy catheters have proven very successful in treating atherosclerosis, problems may arise when using atherectomy catheters to treat in-stent restenosis. When using many atherectomy catheters, including currently available side-cutting catheters, to treat in-stent restenosis, the stent may become entangled with the rotating cutter and/or cutter driveshaft. Such entanglement may lead to stent malapposition from the vessel and/or damage the stent. As an example, as of the filing of this disclosure, SilverHawk™ and TurboHawk™ atherectomy catheters from COVIDIEN are contraindicated for in-stent restenosis at a peripheral vascular site.